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Anton5032's avatar
Anton5032
Copper Contributor
May 29, 2020
Solved

Hybrid Exchange change of SMTP relay connector

Hi All   So we have Hybrid Exchange environment, with few 2010 Exchange boxes on-prem, 1x Exchange 2016 on-prem (as the hybrid) and O365 tenant. Until now we were using one of the EX2010 boxes as ...
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2016
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exchange online
Exchange Server
hybrid
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  • PeterRising's avatar
    PeterRising
    Jun 02, 2020

    Anton5032 

     

    Whenever I setup a connector for this purpose on an Exchange 2016 Server, I always set the security tab options as follows;

     

    I would definitely double and triple check your firewall rules too.  Do you definitely have the Exchange Online IP's all allowed for the Exchange 2016 server?

BrettJhonson's avatar
BrettJhonson
Copper Contributor
May 02, 2024

The issue could be related to the hybrid Exchange 2016 box. The EX2010 box connects properly, however the Exchange 2016 box fails to connect despite having the correct firewall rules. Check the Exchange 2016 box's SMTP relay and connector configurations. Check the IP trust settings in Exchange Online Admin. Investigate any socket failures in the logs. If problems persist, consider contacting Exchange support or checking network parameters for differences. Additionally, confirm compatibility with the https://smtpget.com/smtp-service-provider/, as this may impact connectivity.

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